Since a LCD (liquid crystal device) not only has small weight and slim size but also low power consumption, the LCD has been extensively used. Thus, the LCD has been used for office automation equipment, audio/video apparatus and the like.
The LCD displays a desired image on a screen by adjusting image signals, which are applied to a plurality of switch devices arranged in a matrix type, and the amount of transmitted light.
Since such an LCD is not a self-emitting display device, the LCD requires a light source such as a backlight unit. A CCFL (cold cathode fluorescent lamp) is used as a light source for a backlight unit.
Since the CCFL has low operation current, low power consumption, low heating, high brightness, long life span and the like, the CCFL has been recently used as a light source for a backlight unit of a TFT-LCD and the like. In order to light a lamp such as the CCFL, high AC voltage is required. In order to provide the high AC voltage, a DC/AC converter is used.